This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Definitive conclusions regarding the anti-inflammatory effects of macrolide antibiotics for treatment of asthma are difficult to formulate since their beneficial effects may be related to their antimicrobial action. We hypothesized that azithromycin possesses distinct anti-inflammatory properties and tested this assumption in a non-infectious mouse model of allergic asthma. To induce allergic airway inflammation seven-week-old BALB/cJ mice underwent intraperitoneal ovalbumin sensitization on days 0 and 7 followed by intranasal challenge on day 14. Mice were treated with PBS or azithromycin on days 13 through 16 and on day 17 airway inflammation was assessed by quantifying leukocytes in the airway, expression of multiple inflammatory mediators in the bronchoalveolar lavage (BAL), and mucous cell metaplasia. In a separate set of experiments, azithromycin or PBS treatment were initiated after the ovalbumin challenge. Each experiment was repeated 3 times (a total of 9-11 mice in each group).